NOSQL is an alternative to the traditional Relational Database Management system. It is designed to work with large sets of distributed data. NoSQL databases stores data in the key-value form. Here is the list of Best NoSQL interview Questions and answers

What do you understand by NoSQL in databases?

The database management systems which are highly scalable and flexible are known as NoSQL databases. These databases allow us to store and process unstructured and semi-structured data which is not possible when we make use of Relational database management system. NoSQL can be termed as a solution to all the conventional databases which were not able to handle the data seamlessly. It also gives an opportunity to the companies to store massive amount of structured and unstructured data in real time. In today’s time, big firms such as- Google, Facebook, Amazon, etc. use NoSQL for providing cloud-based services for storing data in real time.

What do you understand by " Polyglot Persistence " in NoSQL?

The term Polyglot Persistence was coined by Neal Ford in 2006 to express the idea that applications should be written in mixed languages. As we all know that different problems arise in all the applications. So, when an application is written using different languages, then those languages can be used to solve or tackle with different kind of problems. This is known as polyglot persistence. Picking the right language for a particular problem can be more productive rather than trying to fit all the aspects of that problem into a single language. Hence, polyglot persistence is the term which is used to define this hybrid approach to persistence.

How does NoSQL database management system budget memory?

The node which manages the data in the NoSQL database store is the replication node. It is also the main consumer of the memory. The java heap and the cache size which are used by the replication node are the important factors in terms of performance. By default, these two things are calculated by NoSQL in terms of the amount of memory available to the storage node. Specification of the available memory for a storage node is recommended. The memory will be evenly divided between all the RN’s if the storage node hosts more than one replication node.

Explain Oracle NoSQL database management system?

The NoSQL database management system is a distributed key-value database. It is designed so that it can provide highly reliable and scalable data. It can make the data storage available across all the configurable set of systems which functions as storage nodes. In this database system, data is stored as key-value pairs. This data is written to a particular storage node. These databases provide a mechanism for the storage and retrieval of data which is composed in a way other than the tabular method which was used in the relational databases.

What do you mean by eventual consistency in NoSQL stores?

Eventual consistency in NoSQL means that when all the service logics have been executed, the system is left in a consistent state. For achieving high availability, this concept is used in the distributed systems. It gives a guarantee that, if new updates are not made to a given data item, then eventually all accesses to that item will return the last updated value. In NoSQL, it is provided in terms of BASE and RDMS also known as ACID properties. Present NoSQL databases provide client applications with guarantee of eventual consistency. Some NoSQL databases like- MongoDB and Cassandra are eventually consistent in some of the configurations.